Stent delivery systems and associated methods

ABSTRACT

Stent delivery systems and associated methods for delivering stents are disclosed herein. In several embodiments, a handle assembly for delivering a stent from a tubular enclosure can include a first lead screw having a first lead thread of a first pitch and first handedness, a second lead screw having a second lead thread of a second pitch and second handedness different from the first handedness, and a housing defining threads of the first and second pitches. The first lead screw can be in mechanical communication with the tubular enclosure, and the second lead screw can be in mechanical communication with the stent. Upon rotation of a portion of the housing, the housing threads can engage the lead screws so as to induce simultaneous translations of the lead screws in opposite directions. The simultaneous translations are configured to deploy the stent from the tubular enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to each of the following U.S.Provisional patent applications:

(A) U.S. Provisional Patent Application No. 61/681,907, filed on Aug.10, 2012 and entitled “HANDLE ASSEMBLIES FOR STENT GRAFT DELIVERYSYSTEMS AND ASSOCIATED SYSTEMS AND METHODS”; and

(B) U.S. Provisional Patent Application No. 61/799,591, filed Mar. 15,2013 and entitled “HANDLE ASSEMBLIES FOR STENT GRAFT DELIVERY SYSTEMSAND ASSOCIATED SYSTEMS AND METHODS.”

Each of the foregoing applications is incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present technology relates to treatment of abdominal aorticaneurysms. More particularly, the present technology relates to handleassemblies for stent graft delivery systems and associated systems andmethods.

BACKGROUND

An aneurysm is a dilation of a blood vessel of at least 1.5 times aboveits normal diameter. The dilated vessel forms a bulge known as ananeurysmal sac that can weaken vessel walls and eventually rupture.Aneurysms are most common in the arteries at the base of the brain(i.e., the Circle of Willis) and in the largest artery in the humanbody, the aorta. The abdominal aorta, spanning from the diaphragm to theaortoiliac bifurcation, is the most common site for aortic aneurysms.Such abdominal aortic aneurysms (AAAs) typically occur between the renaland iliac arteries, and are presently one of the leading causes of deathin the United States.

The two primary treatments for AAAs are open surgical repair andendovascular aneurysm repair (EVAR). Surgical repair typically includesopening the dilated portion of the aorta, inserting a synthetic tube,and closing the aneurysmal sac around the tube. Such AAA surgicalrepairs are highly invasive, and are therefore associated withsignificant levels of morbidity and operative mortality. In addition,surgical repair is not a viable option for many patients due to theirphysical conditions.

Minimally invasive endovascular aneurysm repair (EVAR) treatments thatimplant stent grafts across aneurysmal regions of the aorta have beendeveloped as an alternative or improvement to open surgery. EVARtypically includes inserting a delivery catheter into the femoralartery, guiding the catheter to the site of the aneurysm via X-rayvisualization, and delivering a synthetic stent graft to the AAA via thecatheter. The stent graft reinforces the weakened section of the aortato prevent rupture of the aneurysm, and directs the flow of bloodthrough the stent graft away from the aneurysmal region. Accordingly,the stent graft causes blood flow to bypass the aneurysm and allows theaneurysm to shrink over time.

Most stent and stent graft systems for cardiovascular applications(e.g., coronary, aortic, peripheral) utilize self-expanding designs thatexpand and contract predominantly in the radial dimension. However,other system include braided stent grafts that are delivered in aradially compressed, elongated state. Upon delivery from a deliverycatheter, the stent graft will radially expand and elastically shorteninto its free state. In other words, the effective length of the stentgraft changes as its diameter is forced smaller or larger. For example,a stent graft having a shallower, denser helix angle will result in alonger constrained length. Once the stent graft is removed from aconstraining catheter, it can elastically return to its natural, freelength.

Delivering a stent graft to an artery requires accurate and precisepositioning of the stent graft relative to a target location in thedestination artery. For example, a misplaced stent graft can block flowto a branching artery. Some stent graft delivery systems utilize one ormore markers (e.g., radiopaque markers) to establish the alignment ofthe stent graft relative to the artery wall. However, the location ofthe radiopaque markers on the stent graft can move relative to aninitial marker position because of the change in the stent graft'seffective length upon deployment, as described above. Accordingly, afterdeployment of a stent graft, the stent graft (e.g., its proximal ordistal edge) may miss the target point in the artery. Therefore, thereare numerous challenges associated with the accurate positioning ofstent grafts that change dimensions in both the radial and longitudinaldirections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of a stent graft delivery system configuredin accordance with an embodiment of the technology.

FIGS. 1B and 1C are functional schematic diagrams of a portion of ahandle assembly system configured in accordance with embodiments of thetechnology.

FIG. 2A is an isometric view of a handle assembly configured inaccordance with an embodiment of the technology.

FIGS. 2B and 2C are side views of a delivery catheter of a stent graftdelivery system configured in accordance with an embodiment of thetechnology.

FIGS. 2D and 2E are side views of collets of a stent graft deliverysystem configured in accordance with an embodiment of the technology.

FIGS. 3A-3C are side views of a delivery catheter of a stent graftdelivery system configured in accordance with an embodiment of thetechnology.

FIGS. 4A-4E are front and side views of collets of a stent graftdelivery system configured in accordance with various embodiments of thetechnology.

FIGS. 5A and 5B are partial side views of a handle assembly and ahousing, respectively, configured in accordance with various embodimentsof the technology.

FIG. 6A is a partial cut-away view of a handle assembly configured inaccordance with an embodiment of the technology.

FIGS. 6B-6D are enlarged partial cut-away views of portions of thehandle assembly of FIG. 6A.

FIG. 6E is an isometric view of a portion of the handle assembly of FIG.6A.

FIG. 7 is an enlarged partial cut-away view of a distal portion of thehandle assembly configured in accordance with an embodiment of thetechnology.

FIG. 8A is an isometric view of a handle assembly configured inaccordance with another embodiment of the technology.

FIG. 8B is an enlarged, partially translucent isometric view of aportion of the handle assembly of FIG. 8A.

FIG. 9 is a partial cut-away isometric view of a handle assemblyconfigured in accordance with another embodiment of the technology.

FIGS. 10A and 10B are side and partial cut-away views, respectively, ofa handle assembly configured in accordance with another embodiment ofthe technology.

FIG. 11A is an isometric view of a stent graft delivery systemconfigured in accordance with another embodiment of the technology.

FIGS. 11B and 11C are side views of a delivery catheter of the stentgraft delivery system of FIG. 11A configured in accordance with anembodiment of the technology.

FIG. 11D is a side view of a collet of the a stent graft delivery systemof FIG. 11A configured in accordance with an embodiment of thetechnology.

FIG. 12A is a partial cut-away view of a handle assembly configured inaccordance with an embodiment of the technology.

FIGS. 12B-12D are enlarged partial cut-away views of portions of thehandle assembly of FIG. 12A.

FIG. 13 is a partially translucent isometric view of a portion of ahandle assembly configured in accordance with another embodiment of thetechnology.

FIG. 14 is a partially translucent isometric view of a portion of ahandle assembly configured in accordance with another embodiment of thetechnology.

FIG. 15A is a partial isometric view of a portion of a handle assemblyconfigured in accordance with an embodiment of the technology.

FIG. 15B is an enlarged view of a portion of the handle assembly of FIG.15A.

FIG. 15C is a partially translucent side view of a portion of the handleassembly of FIG. 15A.

FIGS. 16A and 16B are partially schematic representations of a method ofstent graft delivery in accordance with an embodiment of the technology.

FIG. 17 is a partially schematic representation of a method of stentgraft delivery in accordance with an embodiment of the technology.

FIGS. 18A-18E illustrate a stent delivery method in accordance with anembodiment of the technology.

FIGS. 19A-19C illustrate a stent delivery method in accordance withanother embodiment of the technology.

DETAILED DESCRIPTION

The present technology is directed toward handle assemblies for stentdelivery systems and associated systems and methods. Certain specificdetails are set forth in the following description and in FIGS. 1A-19Cto provide a thorough understanding of various embodiments of thetechnology. For example, many embodiments are described below withrespect to the delivery of stent grafts that at least partially repairAAAs. In other applications and other embodiments, however, thetechnology can be used to repair aneurysms in other portions of thevasculature. Furthermore, the technology can be used to deliver a stentfor any suitable purpose in any suitable environment. Other detailsdescribing well-known structures and systems often associated with stentgrafts and associated delivery devices and procedures have not been setforth in the following disclosure to avoid unnecessarily obscuring thedescription of the various embodiments of the technology. Many of thedetails, dimensions, angles, and other features shown in the Figures aremerely illustrative of certain embodiments of the technology. Forexample, dimensions shown in the Figures are representative ofparticular embodiments, and other embodiments can have differentdimensions. A person of ordinary skill in the art, therefore, willaccordingly understand that the technology may have other embodimentswith additional elements, or the technology may have other embodimentswithout several of the features shown and described below with referenceto FIGS. 1A-19C.

In this application, the terms “distal” and “proximal” can reference arelative position of the portions of an implantable stent graft deviceand/or a delivery device with reference to an operator. Proximal refersto a position closer to the operator of the device, and distal refers toa position that is more distant from the operator of the device. Also,for purposes of this disclosure, the term “helix angle” refers to anangle between any helix and a longitudinal axis of the stent graft.

Selected Embodiments of Stent Delivery Systems

As shown in FIGS. 1A-1C, various embodiments of a stent delivery system100 can include a delivery catheter 120 having a shaft or tubularenclosure 124 on a distal end portion of the catheter 120, a braidedstent 110 (FIGS. 1B and 1C) constrained within the tubular enclosure124, and a handle assembly 150 at a proximal end portion of the deliverycatheter 120. Various embodiments of the technology may be used todeliver the braided 110 stent to a target area within a body lumen of ahuman. For example, one embodiment of the stent delivery system 100 canbe configured to deploy a stent at a target location in an aorta suchthat at least a portion of the stent is superior to an aortic aneurysm.As another example, another embodiment of the stent delivery system 100can be configured to deploy a stent at a target location in an iliacartery such that at least a portion of the stent is inferior to anaortic aneurysm. Further embodiments of the technology may be used todeliver a stent to any suitable target area.

1.1 Selected Embodiments of Delivery Catheters and Stents

The delivery catheter 120 of various embodiments can include a distalend portion insertable into a body lumen within a human and navigabletoward a target area, and nested components configured to mechanicallycommunicate actions of the handle assembly 150 to distal end portion ofthe delivery catheter 120. The stent 110 (FIGS. 1B and 1C) can beconstrained in a radially compressed state at the distal end portion ofthe delivery catheter 120. In some embodiments, the delivery catheter120 has a diameter of approximately 14 Fr, but in other embodiments thedelivery catheter 120 can have a greater diameter or a smaller diameter,such as 10 Fr or 8 Fr.

Selected Embodiments of Distal End Portions of Delivery Catheters

FIGS. 2A-2E illustrate an embodiment of a stent delivery system 200configured in accordance with another embodiment of the technology, andFIGS. 3A-3C illustrate portions of a delivery catheter 220 of the stentdelivery system 200 of FIGS. 2A-2C. As shown in FIG. 2A, the stentdelivery system 200 can include the delivery catheter 220 and handleassembly 250 operably coupled to the delivery catheter 220. As shown inFIGS. 2B, 2C, and 3A-3C, the distal end portion of delivery catheter 220includes a distal top cap 222 and an outer sheath 224 that engage astent 210. More specifically, the distal top cap 222 covers andconstrains at least a distal end portion 210 d of the stent 210 in aradially compressed configuration, and the outer sheath 224 covers andconstrains at least a proximal end portion 210 p of the stent 210 in aradially compressed configuration. In some embodiments, the top cap 222and outer sheath 224 can overlap or meet edge-to-edge so as to entirelycover the stent 210, though in other embodiments the top cap 222 andouter sheath 224 can leave a medial portion of the stent 210 uncovered.The top cap 222 can have a tapered distal end to help navigate thecatheter through a patient's vasculature, and/or a radiused proximaledge that may reduce snagging or catching on vasculature or otherfeatures during catheter retraction after stent deployment.

FIGS. 11A-12D show an embodiment of a delivery system 400 configured inaccordance with another embodiment of the technology. Similar to thestent delivery system 200 of FIGS. 2A-2E, the stent delivery system 400of FIGS. 11A-12D can include a delivery catheter 420 and handle assembly450 operably coupled to the delivery catheter 420. As shown in FIGS. 11Band 11C, the distal end portion of the delivery catheter 420 can includea distal top cap 424 having a tubular enclosure that covers andconstrains the entirety of the stent 410 in a radially compressedconfiguration. Removing the top cap 424 in a distal direction can exposethe stent 410. Similar to the top cap 222 shown in FIGS. 2B and 2C, thetop cap 424 can have a tapered distal end and/or radiused proximal edge.

Other embodiments of delivery catheters can have distal end portionsthat include an outer sheath that covers and constrains the entirety ofthe stent in a radially compressed configuration such that retraction ofthe outer sheath in a proximal direction exposes the stent. Furthermore,in some embodiments, the top cap 222, 424 and/or the outer sheath caninclude radiopaque markers that provide visual aids for devicepositioning during deployment procedures. Such radiopaque markers can behelical, circumferential rings, and/or have any other suitable form.Additionally, in some embodiments, the top cap 222, 424 and/or the outersheath can include structural reinforcements, such as filaments, todiscourage deformation in tension or compression. For example,axially-oriented filaments can be interwoven or otherwise coupled to thetop cap 222, 424 or outer sheath such that the top cap 222, 424 or outersheath is stretch-resistant and facilitates smooth, predictableactuation by the various nested components described below. As anotherexample, the top cap 222, 424 and/or outer sheath can include otherreinforcements to increase column strength and discourage bucklingduring actuation by the various nested components.

Selected Embodiments of Stents and Collets

As shown in, for example, FIG. 2B, the stent 210 can be disposed at thedistal end portion of the delivery catheter 220. The stent 210 can be abare stent or a stent graft, such as those described in U.S. ApplicationPatent Publication No. 2011/0130824, which is incorporated herein byreference in its entirety. In other embodiments, the stent 210 can beany suitable braided stent or other self-expanding stent. As describedabove, the stent 210 can be constrained in a radially compressedconfiguration by the top cap 222 and/or an outer sheath. Additionally,as shown in FIG. 2C, prior to stent deployment, the stent (not shown)can be axially constrained at the distal end portion of the deliverycatheter 220 with one or more collets 226, 228 coupled to one or morenested components of the delivery catheter 220.

FIGS. 4A-4E are front and side views of various collets 226, 228 thatare configured to couple stents to the distal end portion of thedelivery catheter 220 (FIG. 2C). Generally, the collets 226 and 228 caneach include a fluted portion with circumferentially distributed prongs227, each of which engages an opening on a stent and constrains thelongitudinal position of the stent at the point of engagement. Eachprong 227 can have a radius of curvature that matches that of the stentit is configured to engage and a height that exceeds the height of thestent wire by a suitable amount so as to help ensure engagement with thestent. For example, the prongs 227 may have a height about 1.5 times theheight of the stent wire. In other embodiments, the prongs 227 may haveother suitable heights. The number, arrangement, and particular prongprofiles can be suitably tailored to the specific application. Forexample, the collets 226 and 228 can include an angled tip, a 5-pointangled tip, a rounded tip that reduces or eliminates friction orundesirable catching on the stent wire, and/or a spring 229 (FIG. 4E)that assists in launching the stent wire into radial expansion duringstent deployment.

Delivery systems in accordance with the present technology can include atrailing or proximal collet 226 (FIGS. 4D and 4E) coupled to a proximalend portion of a stent, a leading or distal collet 228 (FIGS. 4A-4C)coupled to a distal end portion of the stent, or both the trailingcollet 226 and the leading collet 228. In other embodiments, individualcollets can be coupled to other suitable portions of a stent (e.g., amedial portion of a stent). As shown in FIGS. 11B and 11C, in furtherembodiments one or more end portions of a stent can be coupled to thedistal end portion of the delivery catheter 420 with a smooth, pronglessdocking tip 426.

Selected Embodiments of Nested Components

Nested components along the delivery catheters 220 and 420 describedabove can be configured to mechanically control aspects of the distalend portion of the delivery catheter. In various embodiments, each ofthe nested components can be configured to longitudinally moveindependently of the other nested components, whereas in otherembodiments two or more nested components can temporarily or permanentlybe locked together to permit movement in tandem. At least portions ofthe nested components outside of a handle assembly (e.g., the handleassemblies 250 and 450) can be sufficiently flexible to permitnavigation and advancement through potentially tortuous paths through ablood vessel, though the degree of flexibility can vary depending on theapplication (e.g., the location of the target site and/or the path tothe target site). The nested components can include a plurality of tubesand/or wires that are configured to push and/or pull various componentsof the distal end portion of the delivery catheter. As a person ofordinary skill in the art would appreciate, although the components ofthe delivery catheters 220 and 420 are described herein as “nested”, inother embodiments the delivery catheters 220 and 420 can include similaroperative components arranged laterally offset from one another.

FIG. 2C shows an embodiment of the delivery catheter 220 in which thenested components include a tip tube 230, an inner shaft 232, and adilator 236, although in other embodiments the delivery catheter 220 caninclude any suitable number of tubes and/or shafts. As shown in FIGS. 6Aand 6C, in various embodiments, the nested components can furtherinclude one or more stiffeners 234 disposed within and/or around othernested components. The stiffener 234 can, for example, axially reinforcea portion of a pushing component (e.g., the inner shaft 232) to increasethe column strength of the pushing component. The stiffener 234 can bemade of stainless steel or any other suitably rigid material. In theembodiment shown in FIGS. 2C and 6A, the tip tube 230 is disposed withinthe inner shaft 232, and the inner shaft 232 is disposed within thedilator 236, with the stiffener 234 (FIG. 6A) surrounding andreinforcing portions of the tip tube 230 and the inner shaft 232 withinthe handle assembly 250.

In the embodiment shown in FIGS. 2B and 2C, the tip tube 230 isoperatively connected to the top cap 222 such that proximal and distalmovement of the tip tube 230 corresponds to longitudinal movement of thetop cap 222. For example, sufficient distal movement of the tip tube 230can cause the top cap 222 to move distally enough to release the distalend portion 210 d of the stent 210, thereby allowing the distal endportion 210 d of the stent 210 to self-expand. In some embodiments, thetip tube 230 can be made of stainless steel, and in other embodimentsthe tip tube 230 can additionally or alternatively include any othersuitable materials. Furthermore, the tube 230 can include suitablestructural reinforcing features, such as a stainless steel braid.

In the embodiment shown in FIGS. 2A-2E, the inner shaft 232 isoperatively connected to the leading collet 228 engaged with the distalend portion 210 d of the stent 210 such that proximal and distalmovement of the inner shaft 232 corresponds to longitudinal movement ofthe leading collet 228 and distal end portion 210 d of the stent 210. Inother embodiments, the inner shaft 232 can be in mechanicalcommunication with the distal end portion 210 d of the stent 210 inother suitable manners. The inner shaft 232 can permit, within itslumen, telescopic movement of the tip tube 230, thereby allowinglongitudinal movement of the top cap 222 relative to the leading collet228. The inner shaft 232 can be a tube made of polyimide and/or othersuitable materials.

In the embodiment shown in FIG. 2C, the dilator 236 is operativelyconnected to the trailing collet 226, which is in turn engaged with theproximal end portion 210 p of the stent 210 such that proximal anddistal movement of the dilator 236 corresponds to longitudinal movementof the trailing collet 226 and the proximal end portion 210 p of thestent 210. The dilator 236 can permit, within its lumen, telescopicmovement of the tip tube 230 and the inner shaft 232. In turn, the outersheath 224 can permit, within its lumen, the telescopic movement of thedilator 236. Accordingly, the top cap 222, the leading collet 228, andthe trailing collet 226 may move relative to one another correspondingto relative movement of the tip tube 230, the inner shaft 232, and thedilator 236, respectively. The dilator 236 can be made from nylon and/orvarious other suitable materials.

In certain embodiments, the nested components described above withrespect to FIGS. 2C, 6A, and 6C can be used to deliver a stent to anaorta before an aneurysm. In other embodiments, the nested componentscan be used to deliver stents to other blood vessels, such as the iliacarteries.

FIGS. 11A-11C show another embodiment of the delivery catheter 420 inwhich the nested components include a tip tube 430, an inner shaft 432,and a dilator 436, although in other embodiments the delivery catheter420 can include any suitable number of tubes and/or shafts. As shown inFIGS. 12A and 12D, the nested components can additionally include one ormore stiffeners (identified individually as a first stiffener 434 a anda second stiffener 434 b, and referred to collectively as stiffeners434) disposed within and/or around other nested components. Similar tothe embodiment of FIG. 6A, the stiffeners 434 can, for example,reinforce a pushing component for increased column strength of thatpushing component. The stiffeners 434 can be made of stainless steel orany other suitably rigid material. In the embodiment shown in FIG. 11C,a portion of the tip tube 430 is disposed within the inner shaft 432,and another portion of the tip tube 430 is disposed within the dilator436. As shown in FIG. 12A, the first and second stiffeners 434 a and 434b can surround and reinforce another portion of the tip tube 430 withinthe handle assembly 450. In other embodiments, however, the nestedcomponents can be configured in any suitable arrangement. Furthermore,some or all of the nested components can be replaced or supplementedwith wires or other suitable control mechanisms.

In the embodiment of FIGS. 11A-12B, the tip tube 430 is operativelyconnected to the top cap 424 such that the proximal and distal movementof the tip tube 430 corresponds to longitudinal movement of the top cap424. In particular, sufficient distal movement of the tip tube 430 cancause the top cap 424 to move distally enough to release the stent 410,thereby allowing the stent to self-expand. The tip tube 430 can be madeof stainless steel and/or other suitable materials. Furthermore, thetube 430 can include suitable structural reinforcing features, such as astainless steel braid.

As further shown in the embodiment of FIGS. 11A-12B, the inner shaft 432is operatively connected to the leading collet 428, which is in turnengaged with the distal end portion 410 d of the stent 410 such thatproximal and distal movement of the inner shaft 432 corresponds tolongitudinal movement of the leading collet 428 and the distal endportion 410 d of the stent 410. In other embodiments, the inner shaft432 can be in mechanical communication with the distal end portion 410 dof the stent 410 in any suitable manner. Within its lumen, the innershaft 432 can permit telescopic movement of the tip tube 430. The innershaft 432 can be a tube made of polyimide and/or other suitablematerials.

As shown in FIG. 11C, the dilator 436 can be coupled to a docking tip426, which engages with the proximal end portion 410 p of the stent 410at the distal end portion of the delivery catheter 420. Within itslumen, the dilator 436 can permit telescopic movement of the inner shaft432 and the tip tube 430. The dilator 436 is made of nylon and/or othersuitable materials.

In certain embodiments, the nested components described above withrespect to FIGS. 11A-12B can be used to deliver a stent to an iliacartery after an aneurysm. In other embodiments, the nested componentscan be used to deliver stents to other blood vessels, such as the aorta.

Though the above embodiments are described in detail with particulararrangements of nested components, in other embodiments the nestedcomponents can be configured in any suitable arrangement. Additionally,other embodiments can include any suitable number of nested push/pullcomponents. Furthermore, some or all of the nested components can bereplaced or supplemented with wires or other suitable controlmechanisms.

1.2 Selected Embodiments of Handle Assemblies

Various embodiments of handle assemblies can be used in conjunction withother aspects of the stent delivery systems 200 and 400 as describedabove, but can additionally or alternatively be used to deploy anysuitable stent or stent graft constrained within a tubular enclosure ofa delivery catheter in a radially compressed, elongated state. Inparticular, as described in further detail below and demonstrated in thefunctional diagrams of FIGS. 1B and 1C, the handle assembly 150 of FIG.1A can incorporate various mechanisms to effectuate the opposingdisplacement of an uncovering component 160 and a position compensatingcomponent 162 at a predetermined payout ratio, which deploys the stent110 in a controlled manner. The uncovering component or element 160 canalso configured to expose the stent 110 from the tubular enclosure 124and allow the exposed portion of stent 110 to radially self-expand. Theposition compensating component 162 provides an axially compressiveforce on the stent 110 that counteracts the longitudinal displacementotherwise resulting from changing stent length as the stent 110 radiallyexpands. Generally speaking, as shown in FIG. 1B, the positioncompensating component 162 can actuate in a distal direction while theuncovering element 160 can actuate in a proximal direction.Alternatively, as shown in FIG. 1C, the positioning compensatingcomponent 162 can actuate in a proximal direction while the uncoveringcomponent 160 can actuate in a distal direction.

The synchronized motion of the uncovering component 160 and the positioncompensating component 162 can control the axial position of the exposedportion of the stent 110. When the ratio of the components' movements ismatched to or corresponds to the helix angle of the stent 110, theposition of the deployed stent 110 can be maintained relative to aparticular destination target location. Although in many applications itis desirable that at least one end of the stent 110 remain stationaryduring deployment, in some alternative applications it might bedesirable to modify the predetermined payout ratio so that the exposedportion of the stent 110 moves in a controlled manner at a predeterminedrate.

Selected Embodiments of Lead Screws

FIGS. 5A-12D illustrate various handle assemblies with lead screwsconfigured in accordance with embodiments of the technology. Forinstance, as shown in FIGS. 5A and 5B, various embodiments of a handleassembly for delivering a stent from a tubular enclosure (e.g., thetubular enclosure 124 of FIG. 1A) can include a first lead screw 260, asecond lead screw 262, and a housing 270 surrounding at least a portionof each of the first and second lead screws 260 and 262. The first leadscrew 260 has a lead thread of a first pitch and a first handedness(i.e., the lead screw has a right-handed or left-handed thread), and iscoupled to the tubular enclosure. The second lead screw 262 has a leadthread of a second pitch and a second handedness different from thefirst handedness, and is coupled to the stent. The housing 270 surroundsat least a portion of each of the first and second lead screws 260 and262, and defines two housing threads, including a first housing thread276 with the same pitch and handedness as the first lead screw 260 and asecond housing thread 278 with the same pitch and handedness as thesecond lead screw 262. The housing 270 and lead screws 260, 262 can beconfigured to cooperate such that upon rotation of at least a portion ofthe housing around a longitudinal axis, the first housing thread 276engages the first lead screw 260 and second housing thread 278 engagesthe second lead screw 262. The engagements between the housing threads276, 278 and the lead screws 260, 262 induce simultaneous translationsof the first and second lead screws 260 and 262 in opposite directionsalong a longitudinal axis A-A (FIG. 5A) of the housing 270, and thesimultaneous translations deploy the stent from the tubular enclosure.In particular, translation of the first lead screw 260 can cause thetubular enclosure to translate to expose the stent and allow the exposedportion of the stent to radially self-expand. At the same time,translation of the second lead screw 262 can apply an axiallycompressive force to the stent that substantially avoids orcounterbalances longitudinal displacement of the end of the stent thatis initially exposed.

As shown in FIGS. 5A-12D, various embodiments of handle assemblies caninclude first and second lead screws that have different handedness suchthat their rotation in the same direction induces their movement inopposite directions. For example, the first lead screw can have aright-handed thread, and the second lead screw can have a left-handedthread. Alternatively, the first lead screw can have a left-handedthread, and the second lead screw can have a right-handed thread. Sincethe first and second lead screws have threads of opposite handedness,their concurrent rotation in the same direction will induce theirtranslations in opposite directions. Additionally, the threads of leadscrews can be external threads (e.g., as shown in FIG. 5A) or internalthreads.

Furthermore, as shown in FIGS. 5A-12D, the first and second lead screwsin various embodiments of the handle assembly can have different threadpitches such that their concurrent rotation induces their movement atdifferent rates of travel. As shown in FIG. 5A, for example, the firstlead screw 260, which is in mechanical communication with the tubularenclosure, can have a relatively coarse thread pitch, and the secondlead screw 262, which is in mechanical communication with the proximalor distal end portion of the stent, can have a relatively fine threadpitch. Alternatively, the first lead screw 260 can have a relativelyfine thread pitch, while the second lead screw 262 can have a relativelycoarse thread pitch, or the first and second lead screws 260 and 262 canhave substantially equal thread pitches. The ratio of thread pitchescorresponds to a predetermined payout ratio of the first and second leadscrews 260 and 262 and, in various embodiments, can correspond to thebraid angle of the stent. In certain embodiments, for example, the ratioof the coarse thread (e.g., on the first lead screw 260) to the finethread (e.g., on the second lead screw 262) is approximately 1.5:1.Payout ratios ranging from about 1:1 to about 2:1 have also been shownto provide acceptable stent deployment. In other embodiments, the payoutratio of the first and second lead screws 260 and 262 can differdepending on the application. For example, both the first and secondlead screws 260 and 262 can have relatively fine thread pitches that mayallow for precise deployment, since a fine lead screw axially translatesless distance per rotation than a coarse lead screw would for the samerotation. In this manner, the specific pitches and/or the ratio of thepitches can be selected to achieve a particular degree of mechanicaladvantage, a particular speed and precision of stent deployment, and/ora selected predetermined payout ratio.

As shown in FIGS. 5A-12D, the first and second lead screws can havecross-sections that enable them to longitudinally overlap and slideadjacent to each other along the longitudinal axis of the handle. Asshown in FIG. 5A, for example, at least the threaded lengths of the leadscrews 260, 262 are “half” lead screws, each having an approximatelysemi-circular cross-section and arranged so that the lead screws 260,262 are concentric. When mated longitudinally, the semi-circularcross-sections cooperate to define a lumen through which variouspush/pull tubes, wires, and/or other suitable mechanisms for stentdeployment can travel and extend distally into the delivery catheter. Inother embodiments, the first and second lead screws 260 and 262 can haveother complementary arcuate cross-sections, and/or other suitablecross-sectional shapes.

In various embodiments, the lead screws 260 and 262 can have an initialoffset arrangement prior to stent deployment such that the first andsecond lead screws 260 and 262 have no longitudinal overlap within thehousing 270 or overlap for only a portion of the length of the leadscrews 260, 262. Upon rotation of the housing 270, the lead screws 260,262 can translate relative to one another to increase their longitudinaloverlap. In certain embodiments, for example, the lead screws 260, 262in the initial offset arrangement have an initial overlap area ofapproximately five to nine centimeters (e.g., seven centimeters). Inoperation, the handle assembly can be configured such that rotation ofthe housing 270 during the course of stent deployment induces the firstlead screw 260 (and movement of the tubular enclosure coupled thereto)to axially translate a distance of approximately 15 to 25 centimetersrelative to its position in the initial offset arrangement.Additionally, the handle assembly can be configured such that rotationof the housing during the course of stent deployment induces the secondlead screw 262 (and movement of the associated end of the stent) toaxially translate a distance of approximately 5 to 15 centimeters. Forexample, in one embodiment the second lead screw 262, which is inmechanical communication with an end of the stent, is configured toshorten the length of the stent (relative to the length of the stent inits elongated radially compressed configuration) by approximately 25% to75% (e.g., approximately 50%). In other embodiments, the degree ofchange in the stent length pre-deployment to post-deployment can differdepending on the specific application. In other embodiments, rotation ofthe housing 270 during stent deployment can cause the first lead screw262 to axially translate more than 25 centimeters or less than 15centimeters from its initial position, and cause the second lead screw262 to axially translate more than 15 centimeters or less than 5centimeters from its initial position.

In various embodiments, the first and second lead screws 260 and 262 candefine additional mating features to facilitate mutual alignment. Forexample, one lead screw (e.g., the first lead screw 260) can define alongitudinal key or spline that slidingly engages with a longitudinalslot on the other lead screw (e.g., the second lead screw 262) such thatthe lead screws maintain longitudinal alignment with each other as thelead screws longitudinally translate past one another. In otherembodiments, one or both lead screws can include other suitablealignment features.

The first and second lead screws 260 and 262 can be made of injectionmolded plastic of suitable column strength and overall torsionalrigidity to bear axial loads and/or torsional loads during stentdeployment. In other embodiments, the lead screws 260, 262 canadditionally or alternatively include other suitable materials that aremilled, turned, casted, and/or formed in any suitable manufacturingprocess to create the threads and other associated features of the leadscrews 260, 262. The lead screws 260, 262 can additionally oralternatively meet predetermined load requirements by includingparticular thread types (e.g., acme threads or other trapezoidal threadforms) and/or material reinforcements. In some embodiments, the plasticmaterial is of a formulation including a lubricant for low-frictionthread engagement, such as LUBRILOY® D2000. Furthermore, suitableexternal lubricants can additionally or alternatively be applied to thelead screws 260, 262 to help ensure smooth engagement of the threads.

As shown in FIGS. 5A-12D, in various embodiments of the handle assembly,the housing can include a stationary portion and rotatable shaftportion. As shown in FIG. 5A, for example, the housing 270 can include afirst or rotatable shaft portion 252 a and a second or stationaryportion 252 b coupled to one another and secured by a locking collar254. Though the first shaft portion 252 a is referred to herein as the“rotatable shaft portion 252 a” of the housing 270 and the second shaftportion 252 b is referred to as the “stationary shaft portion 252 b”, itshould be understood that in other embodiments either the first orsecond shaft portion 252 a or 252 b can be rotated in an absolute frameof reference, and/or rotated relative to the other shaft portion 252 a,252 b. As shown in FIG. 5B, the rotatable shaft portion 252 a can definehousing the first and second housing threads 276 and 278 that areconfigured to threadingly engage with corresponding threads on leadscrews 260 and 262. Accordingly, rotation of the rotatable shaft portion252 a relative to the stationary shaft portion 252 b can cause the firstand second threads 276 and 278 to engage the corresponding threads onlead screws 260 and 262, and therefore cause the first and second leadscrews 260 and 262 to axially translate. In other embodiments, anysuitable portion of the housing 270 can define the threads 276 and 278.Similarly, FIG. 11A illustrates another embodiment in which the housing470 includes a first or rotatable shaft portion 452 a and a second orstationary portion 452 b that are coupled to one another and secured bya locking collar 454.

In some embodiments, as shown in FIG. 5B, the housing 270 definesinternal threads configured to engage with the externally threaded leadscrews 260, 262 (FIG. 5A). In other embodiments, the housing 270 candefine external threads configured to engage with internally threadedlead screws. In some embodiments, as shown in FIGS. 5A and 5B, thestationary shaft portion 252 b (or another suitable part of housing 270)can include one or more keyway splines 279 (FIG. 5B), and/or any othersuitable key mechanism. Each keyway spline 279 can engage a respectiveaxial groove 269 (FIG. 5A) in one of the lead screws 260, 262 to preventrotation of the lead screws 260, 262 when the rotatable shaft portion252 a rotates, thereby substantially constraining the lead screws 260,262 to axial translation only.

The housing 270 can include shell pieces that mate and couple to oneanother to form the stationary shaft portion 252 b and the rotatableshaft portion 252 a. The shell pieces can define keys and/or otherinterlocking or alignment features to properly mate and form a volume orenclosure that is configured to house or otherwise contain the first andsecond lead screws 260 and 262 and/or other catheter components. Theshell pieces can be snap fit together, attached by screws and/or othermechanical fasteners, and/or otherwise joined. Similar to the first andsecond lead screws 260 and 262, the portions of the housing 270 can becomposed of a suitable rigid plastic formed by injection molding. Inother embodiments, the housing 270 can additionally or alternativelyinclude any other suitable materials and/or be formed by casting,turning, milling, and/or any other suitable manufacturing process. Invarious embodiments, the housing 270 can be made of a lubricious plasticmaterial and/or coated with external lubricant to facilitate smooththread engagement with the lead screws 260, 262 and relative rotationbetween the rotating and stationary shaft portions 252 a and 252 b ofthe housing 270.

FIGS. 6A-6E show an embodiment of the handle assembly 250 with the firstand second lead screws 260 and 262. In this embodiment, the handleassembly 250 is configured to deploy, from the outer sheath 224 or othertubular enclosure, a distal end of the stent (not shown) before theproximal end of the stent during stent delivery. By deploying the distalend of the stent first and maintaining the axial position of the exposeddistal end of the stent, the handle assembly 250 enables accurate andprecise positioning of the distal end of the stent. This functionalitycan be useful for applications where accurate and precise placement ofthe distal end of the stent is clinically necessary. For example, thenthe aorta is accessed through the femoral artery (as is typical of EVARprocedures for AAA repair), this embodiment of handle assembly 250 canbe used to deploy a stent graft in a known region of healthy aortictissue that is superior to an aortic aneurysm but inferior to a renalartery. Precise superior positioning of the distal end of the stent isexpected to increase (e.g., maximize) coverage of and sealing to healthyaortic neck tissue without blocking blood flow into the renal artery. Inother embodiments, the handle assembly 250 may be used in various otherapplications that require or benefit from accurate placement of a distalend of the stent (with respect to the handle operator) 1.

In the embodiment shown in FIGS. 6A-6E, the first lead screw 260 isdirectly or indirectly coupled to a tubular enclosure that can translatein a proximal direction to expose the stent. For example, as shown inFIGS. 6A and 6B, the first lead screw 260 can be coupled to outer sheath224 of the delivery catheter such that translation of the first leadscrew 260 actuates corresponding translation of the outer sheath 224. Incertain embodiments, the first lead screw 260 can be coupled to a distalcoupler 242, which is in turn coupled to the outer sheath 224 such thatproximal and distal movement of the first lead screw 260 corresponds toproximal and distal movement of the outer sheath 224. For instance,sufficient proximal movement of the first lead screw 260 and distalcoupler 242 will cause the outer sheath 224 to move proximally enough toexpose the distal portion of the stent, thereby allowing the exposedportion of the stent to expand. Alternatively, the coupling between thefirst lead screw 260 and the outer sheath 224 can include any suitablemechanical communication between the first lead screw 260 and a tubularenclosure housing a stent. For example, the first lead screw 260 can becoupled directly to the tubular enclosure, coupled to a push or pulltube, a wire, and/or another suitable mechanism that is in turn coupledto the tubular enclosure. The first lead screw 260 can be coupled to thedistal coupler 242 and/or other coupling epoxy, snap fit couplerdesigns, and/or any suitable mechanical fasteners. However, the couplingcan additionally or alternatively include any suitable kind of couplingthat effectuates movement of the tubular enclosure.

As shown in FIGS. 6A-6E, the second lead screw 262 can be directly orindirectly coupled to a proximal end of the stent (not shown) such thattranslation of the second lead screw 262 actuates correspondingtranslation of the proximal end of the stent. As shown in FIG. 6D, thesecond lead screw 262 is configurable to be mechanical communicationwith a proximal coupler 240 that is coupled to dilator 236, which is inturn coupled to the proximal end of the stent (e.g., as shown in FIG.2C). For example, the second lead screw 262 can have a couplerengagement surface 264 in the same longitudinal path as the proximalcoupler 240 such that when second lead screw 262 moves a sufficientdistance in a distal direction, the coupler engagement surface 264 willabut the proximal coupler 240. After this engagement occurs, distalmovement of the second lead screw 262 will cause corresponding distaladvancement of the proximal coupler 240, the dilator 236, and theproximal end of the stent. Alternatively, the coupling between thesecond lead screw 262 and the proximal end of the stent (or othersuitable stent portion) can include any suitable mechanicalcommunication, such as those described above regarding the couplingbetween the first lead screw 260 and the outer sheath.

The handle assembly 250 can further include a stent compressor inmechanical communication with a first portion (e.g., a distal portion)of the stent and independently movable relative to a second portion ofthe stent such that movement of the stent compressor is independent ofthe lead screws 260, 262 and corresponds to axial compression and radialexpansion of the stent. In the embodiment illustrated in FIG. 6E, forexample, the stent compressor is defined by an axial compression slider280 that is in mechanical communication with the distal end of the stentindependent of the first and second lead screws 260 and 262. In otherembodiments, the handle assembly 250 can include The axial compressionslider 280 can be configured to axially compress the stent to facilitatepositioning and longitudinal and rotational orientation. In particular,after the stent has been partially exposed and the exposed portion ofthe stent is able to radially expand, longitudinal proximal movement ofthe axial compression slider 280 can cause radial expansion and/orsupplement self-expansion of the exposed portion of stent. In thismanner, a practitioner can partially deploy the stent in a “jackhammer”type motion to compress the braided stent, reposition the stent asnecessary to best interface with the vasculature (e.g., achieveopposition between the vessel wall and stent graft to form or confirm aseal) and/or other adjacent device components, and then fully deploy thestent by allowing the stent to self-expand (or supplementing radialexpansion with the axial compression slider 280) without constraint bythe outer sheath, top cap, and/or distal collet. Furthermore, thepractitioner can make adjustments by manipulating the axial compressionslider 280 in a stent tensioning direction, thereby radially compressingthe stent again to allow for repositioning of the stent.

In one embodiment, the axial compression slider 280 is configured toexpand the stent from a first radius when in its radially compressedconfiguration to a deployment radius that is sufficiently large to forman at least substantially fluid-tight seal against the vessel in whichthe stent is being deployed. For example, the axial compression slider280 can be configured to expand from a smaller first radius to a largerdeployment radius, where the deployment radius is between approximatelythree and five times the first radius (e.g., at least four times thefirst radius). However, in other embodiments the expansion ratio, orother relative change in cross-sectional stent dimension (e.g.,diameter), can depend on the specific application.

Referring to FIG. 6C, the axial compression slider 280 (FIG. 6E) canengage a distal bearing assembly 282, which is coupled to an inner shaft232 by epoxy or any suitable fastening means. The inner shaft 232 can bein mechanical communication with the distal end of stent. Longitudinalmovement of the compression slider 280 can correspond to longitudinalmovement of the distal bearing assembly 282. The distal bearing assembly282 can ride within one or more slots 274 on opposite sides of thehandle housing 270 (FIG. 6A), and this longitudinal movement of thebearing assembly 282 can correspond to longitudinal movement of thedistal end of the stent. In various embodiments, (e.g., when theproximal end of the stent is substantially stationary), proximalmovement of the slider 280 will proximally pull the distal end of thestent so that the stent is in an axially compressed, radially expandedstate. Similarly, distal movement of the slider 280 after some stentcompression will distally extend the distal end of the stent so thestent is in a tensioned, radially constrained state, thereby allowingthe practitioner to reposition the subsequently constrained stentrelative to the vasculature. As shown in FIG. 6E, the axial compressionslider 280 can include a locking tab 284 that selectively engages withone or more notches 272 (FIGS. 6A and 6C) and/or other types of lockingportions on the handle of the housing 270. Engagement of the locking tab284 with one of the notches 272 enables the operator to fix longitudinalposition of the partially expanded/deployed stent in anticipation offull deployment. When the locking tab 284 is disengaged from the notches272, such as by a depression of a lever or button by the deviceoperator, the slider 280 is free to longitudinally move and axiallycompress the stent. When the locking tab 284 is engaged with one of thenotches 272, the longitudinal position of the slider 280 is set. Invarious embodiments, the set of notches 272 can correspond to discretedegree of stent compression that the operator can use to gauge stentdeployment. In other embodiments, the handle assembly 250 can includeany suitable locking mechanism for securing the longitudinal position ofslider 280.

Other variations of the handle assembly 250 can include other mechanismsfor facilitating axial stent compression independently of the first andsecond lead screws 260 and 262. For example, the embodiment of FIGS. 8Aand 8B includes an axial compression slider 380 and/or other stentcompressor that can be used to rotationally and longitudinallymanipulate a compression coupler 384, which is coupled to the innershaft by epoxy and/or any suitable fastening means. Similar to theslider 280 described above with reference to FIGS. 6A-6E, longitudinaltranslation of the slider 380 corresponds, through mechanicalcommunication, to longitudinal movement of the distal end portion of astent for selective and reversible axial compression of the stent. Asshown in FIG. 8B, the longitudinal position of the slider 380 can belocked by rotating the slider 380 so that the coupler 384 engages one ofthe plurality of slider lock notches 382 in the handle housing. Asanother example, the embodiment of FIG. 9 includes a compression leadscrew 380′ coupled to the inner shaft by epoxy or any suitable fasteningmeans. Rotation of the compression lead screw 380′ will result in itslongitudinal translation and corresponding longitudinal motion of theinner shaft and distal end portion of the stent for selective andreversible axial compression of the stent.

Referring back to FIGS. 6A-6E, the handle assembly 250 embodiment canfurther include a top cap slider 290 (FIG. 6E) that is configured todistally move the top cap 222. The top cap slider 290 can engage aproximal bearing assembly 292 (FIG. 6C), which is coupled to the tiptube 230 by epoxy or any suitable fastening means. Like the distalbearing assembly 282, the proximal bearing assembly 292 can ride alongone or more slots 274 on opposite sides of the handle housing during itslongitudinal movement. Because tip tube 230 is in mechanicalcommunication with the top cap 222, longitudinal movement of the top capslider 290 corresponds to longitudinal movement of the top cap 222. Inparticular, sufficient distal movement of the top cap slider 290 cancompletely expose a distal end portion of the stent. As shown in FIG.6E, the top cap slider 290 can be selectively coupled to the axialcompression slider 280 by means of a removable slider collar 294. Whenthe slider collar 294 is coupled to both the compression slider 280 andthe top cap slider 290 (e.g., with a snap fit or fasteners) thecompression slider 280 and the top cap slider 290 can move in tandem.When the slider collar 294 is removed, the compression slider 280 andthe top cap slider 290 are movable independent of one another. In someembodiments, the top cap slider 290 can also be locked directly to thecompression slider 280 by a snap fit and/or other suitable fasteners(e.g., after the slider collar 294 is removed). An alternativeembodiment of the top cap slider 290 is shown in FIGS. 10A and 10B, inwhich the top cap slider 290 is positioned on the proximal end portionof the housing and engages proximal bearing assembly 292 in a mannersimilar to that described above.

Other variations of the handle assembly 250 can include other mechanismsfor moving a top cap. For example, the embodiment of FIGS. 8A and 8Bincludes a tip release screw 390. When turned, the tip release screw 390can move distally and cause the top cap to move distally and release thedistal end portion of the stent. The threads of the tip release screw390 can prevent accidental deployment as the result of pushing axiallyon the head of the tip release screw 390. As another example, theembodiment of FIG. 9 includes a tip release pusher 390′. When pushed ina distal direction, the tip release pusher 390′ moves distally andcauses the top cap to move distally and release the distal end portionof the stent. In these and other embodiments, additional locks and/orother safety mechanisms (e.g., collars, mechanical fasteners, mechanicalkeys, etc.) can be removeably coupled to the mechanisms for moving thetop cap to reduce the likelihood of accidental or premature deploymentof the top cap.

FIGS. 11A-12D show another embodiment of the handle assembly 450 withthe first and second lead screws 460 and 462. In this embodiment, thehandle assembly 450 is configured to deploy, from a tubular enclosure420 (FIG. 11A), a proximal end portion 410 p of the stent 410 before thedistal end portion 410 d of the stent 410 during a “reverse deployment”stent delivery. By deploying the proximal end portion 410 p of the stent410 first and maintaining the axial position of the exposed proximal endof the stent 410, the handle assembly 450 can facilitate accurate andprecise positioning of the proximal end portion 410 p of the stent 410.This functionality can be useful for applications in which it isimportant to align the proximal end of the stent 410 correctly. Forexample, assuming an approach through the femoral artery typical of EVARprocedures for AAA repair, this embodiment can be used to deploy a stentgraft in an iliac artery for overlapping and sealing with an implantedaortic stent as it may be desirable to ensure that (1) adequate stentlength will be deployed in the iliac artery, and/or (2) no vesselsbranching from the iliac artery (e.g., the hypogastric artery) areinadvertently blocked. In other embodiments, the handle assembly 450 maybe used in other applications that benefit from accurate and preciseplacement of a proximal end of the stent.

In the embodiment of the handle assembly 450 shown in FIGS. 11A-12D, thefirst lead screw 460 can be directly or indirectly coupled to a tubularenclosure that can travel in a distal direction to expose the stent. Forexample, the first lead screw 460 can be in mechanical communicationwith the top cap 424 of the delivery catheter such that distaltranslation of the first lead screw 460 actuates corresponding distaltranslation of the top cap 424. As shown in FIG. 12D, the first leadscrew 460 can be coupled to a proximal coupler 440, which is in turncoupled to the tip tube 430, and the tip tube 430 is coupled to the topcap 424. In particular, sufficient distal movement of the first leadscrew 460 and the proximal coupler 440 will cause the top cap 424(and/or any outer sheath attached to and extending the top cap 424 alongthe stent) to move distally enough to expose the proximal end portion ofthe stent, and additional distal motion of the first lead screw 460 willeventually cause top cap 424 to release the entire length of the stent,thereby allowing the stent to self-expand. Alternatively, the couplingbetween the first lead screw 460 and the top cap 424 can include anyother suitable mechanical communication between the first lead screw 460and the top cap 424, such as the direct or indirect methods describedabove with respect to the embodiment of FIGS. 6A-6E. In furtherembodiments, the coupling can additionally or alternatively include anysuitable kind of coupling that effectuates movement of the distal topcap 424.

In the embodiment of the handle assembly 450 shown in FIGS. 11A-12D, thesecond lead screw 462 is directly or indirectly coupled to a distal endportion 410 d of the stent 410 such that translation of the second leadscrew 462 actuates corresponding translation of the distal end portion410 d of the stent 410. The second lead screw 462 can be configured tobe in mechanical communication with the distal coupler 442 (FIG. 12C),which is coupled to the inner shaft 432, and the inner shaft 432 isengaged with the distal end portion 410 d of the stent 410 by theleading collet 428. More particularly, as shown in FIG. 12C, the secondlead screw 462 has a coupler engagement surface 464 moving within a neck444 of the distal coupler 442 such that when second lead screw 462 movesproximally enough across the neck 444, the coupler engagement surface464 will abut and engage the distal coupler 442. After this engagementoccurs, additional proximal movement of the second lead screw 462 willcause corresponding proximal advancement of the distal coupler 442, theinner shaft 432, and the distal end portion 410 d of the stent 410.Alternatively, the coupling between the second lead screw 462 and thedistal end portion 410 d of the stent 410 (or any suitable stentportion) can include any suitable mechanical communication.

FIG. 13 is a partially transparent, isometric view of a portion of ahandle assembly 550 configured in accordance with another embodiment ofthe technology. The handle assembly 550 can include a first lead screw560 having a first pitch and a second lead screw 562 having a secondpitch different from the first pitch. Similar to the handle assembliesin the embodiments described above, one of the lead screws 560 or 562 isin mechanical communication with a tubular enclosure surrounding astent, and the other lead screw 560 or 562 is in mechanicalcommunication with either a proximal or distal end portion of the stent.The first and second lead screws 560 and 562 can be of oppositehandedness and engaged with a shaft 564 such that a clockwise orcounterclockwise rotation of the shaft 564 will cause the lead screws560, 562 to axially translate in opposite directions. In somevariations, second lead screw 562 can be internally threaded with athread corresponding to the pitch and handedness of first lead screw560, such that the first lead screw 560 can pass longitudinally withinthe second lead screw 562 as the lead screws 560, 562 axially translate.

FIG. 14 illustrates a handle assembly 650 configured in accordance withyet another embodiment of the technology. The handle assembly 650 caninclude a series of coaxial, nested first and second racks 660 and 662that engage with respective first and second pinions 670 and 672 suchthat the movements of racks 660, 662 and pinions 670, 672 areinterrelated by gearing. One of the racks 660 or 662 can be configuredto be coupled to a tubular enclosure (e.g., a catheter or top cap), andthe other rack 660 or 662 can be configured to be coupled to a stent(e.g., using similar attachment mechanisms as described above).Variations of the handle assembly 650 of FIG. 14 can include differentactuation inputs that induce opposing movement of the racks 660 and 662.For example, rotation of either the first pinion 670 or the secondpinion 672 by a handle component (not shown) will effectuate thesimultaneous longitudinal translations of the first and second racks 660and 662 in opposite directions. Alternatively, actuation of either thefirst rack 660 or the second rack 662 by a handle component (not shown)will be translated through the gearing to effectuate the simultaneouslongitudinal translation of the other rack 660 or 662 in an oppositedirection. The pitches of the racks 660, 662 and the pinions 670, 672can vary to facilitate different absolute and relative rates of travelof the racks 660, 662 for each revolution of the pinions 670, 672. Instill other embodiments, the handle assembly 650 can include suitableadditional features, and/or have a different suitable gearingconfiguration.

Other Aspects of Handle Assemblies

In some embodiments, the handle assemblies described above can include adelay system that delays the synchronized actions of exposing a stentand axially compressing the stent until after a portion of the stent isexposed. In particular, in some variations, the delay system delaysmechanical communication between a moving position compensating elementand the stent until a predetermined portion of the stent is exposed froma tubular enclosure. In other variations, the delay system delaysmovement of the position compensating element until a predeterminedportion of the stent is exposed from the tubular enclosure. The delaycan be based on, for example, the distance that the tubular enclosuremust travel before beginning to expose the stent. The delay system canaccordingly avoid premature radial expansion of the stent within thetubular enclosure.

FIG. 6D illustrates one embodiment of a delay system in which there is aspatial longitudinal offset between the proximal coupler 240 and thecoupler engagement surface 264 of the second lead screw 262. Thelongitudinal offset corresponds to a predetermined delay distance. Uponrotation of the shaft portion of the handle assembly, both the first andsecond lead screws 260 and 262 begin to move in opposite directions, butbecause of the longitudinal offset between the coupler engagementsurface 264 of the second lead screw 262 and the proximal coupler 240,the coupler engagement surface 264 does not abut the proximal coupler240 until the second lead screw 262 has traversed the offset. In otherwords, rotation of the handle actuates both lead screws 260, 262, butduring an initial delay lasting until the coupler engagement surface 264has traversed the predetermined delay distance, rotation of the handlecan result in translation of first lead screw 260 to partially exposethe stent without resulting in axial compression of the stent.

FIG. 12C illustrates another embodiment of a delay system in which thedistal coupler 442 with the neck 444 is responsible for a delay insynchronization, where the length of the neck 444 is equal to apredetermined delay distance. Upon rotation of the shaft portion of thehandle assembly 450, both the first and second lead screws 460 and 462begin to move in opposite directions, but because of the neck 444 ofdistal coupler 442, the coupler engagement surface 464 of the secondlead screw 462 does not abut the shoulder of the distal coupler 442until the second lead screw 462 has traversed the neck 444. In otherwords, similar to the embodiment of FIG. 6D, rotation of portions of thehandle assembly 450 actuates both lead screws 460, 462, but during aninitial delay lasting until the coupler engagement surface 464 hastraversed the predetermined delay distance across the coupler neck 444,rotation of the handle can result in translation of the first lead screw460 to partially expose the stent, without resulting in axialcompression of the stent.

In other embodiments of delay systems, the proximal or distal couplercan be in a reverse configuration with respect to the uncovering elementand the position compensating element, and/or the delay system caninclude other components to facilitate a delay. Furthermore, in someembodiments, the handle assembly does not include a delay system todelay axial compression of the stent. In an auto-compression embodiment,the simultaneous actions of exposing the stent and axially compressingthe stent can be carefully synchronized (e.g., with no delay of eitheraction) with relative rates appropriate so that a suitable amount ofaxial compression is performed at the same time the stent is initiallyexposed.

In some embodiments, the housing can include a mechanism that operatesadditionally or alternatively to the axial compression slider 280 (FIG.6E) and radially compresses the stent diameter after partial deployment.For example, as shown in FIGS. 10A and 10B, the handle assembly caninclude a repositioning ring 281 that, when moved longitudinally alongthe axis of the housing, can be used to reduce the outer profile of astent that has been axially compressed to a radially expanded state(e.g., by simultaneous auto-compression as described above, or by anindependent axially compressing component). The repositioning ring 281can be in mechanical communication with an end portion of the stent by apush or pull tube such that proximal or distal movement of therepositioning ring 281 causes corresponding movement of an end of thestent, thereby extending and radially contracting the stent.

As another example, the stent can be undeployed by backdriving the shaftportion of the handle, rotating the shaft portion in a directionopposite the direction required for deployment, such as to reverse thepaths of the lead screws. In this reverse deployment, the stent becomeselongated and radially compressed, and the sheath recovers the exposedportion of the stent. Once the stent returns to its radially compressedstate, the device operator can reposition the stent relative to thesurrounding environment.

As shown in FIG. 15A, in some embodiments the housing further includes arotational control mechanism 350 that limits rotation of the shaftportion to rotation in a deployment direction (i.e., the direction thatactuates stent deployment). In preventing the rotation of the shaftportion in the direction opposite the deployment direction, therotational control mechanism 350 can prevent axial compression of thestent when the stent is still radially constrained in the tubularenclosure, as well as selectively lock against reverse deployment whilestent deployment is in progress. In some embodiments, the rotationalcontrol mechanism 350 can be selectively disengaged so as to selectivelypermit rotation in the direction opposite the deployment direction, suchas to permit reverse deployment. When the rotational control mechanism350 is disengaged, the shaft portion can be rotated in the directionopposite the deployment direction in order to reconstrain the stentwithin the tubular enclosure. By permitting reverse deployment, thehandle assembly can allow repositioning of the entire stent even afterthe stent has been partially deployed, if so desired.

As shown in FIGS. 15A-15C, a locking collar can define at least onechannel 352 and the rotatable shaft portion can define at least onespring tab 354. As long as the rotational control mechanism 350 isengaged, the spring tab 354 flexes to accommodate rotation of the shaftportion in the deployment direction, but the spring tab 354 engages andstops against the channel 352 when the shaft portion is rotated in thedirection opposite of the deployment direction. When the spring tab 354stops against the channel 352, tactile and/or audio clicking feedbackcan inform the handle operator that he or she has rotated the shaft inan impermissible direction. The locking collar can include multiplechannels 352 (e.g., four channels 352 equally circumferentiallydistributed around the collar), such that a single spring tab 354 on theshaft portion permits no more than ninety degrees of rotation in thenon-deployment direction. However, in other embodiments the rotationalcontrol mechanism 350 can include any suitable number of channels 352and/or spring tabs 354. Disengagement of the rotational controlmechanism 350 can be performed, for example, by sliding the lockingcollar distally or proximally out of the rotational path of the springtab 354. For example, as shown in FIG. 15C, moving the locking collarboth rotationally and longitudinally to navigate a key 358 on the shaftportion through a guide path slot 356 in the locking collar will permitthe locking collar to be oriented in a manner where the spring tab 354will not engage with channel 352. Alternatively, the locking collar canbe completely removed to disengage the rotational control mechanism 350.Furthermore, the housing can additionally or alternatively include othersuitable features for selectively restraining rotation of the shaftportion to one direction.

In some embodiments, the housing additionally or alternatively includesother control mechanisms that selectively prevent rotation in adeployment direction. For example, the housing can include an additionalor alternative rotational control mechanisms that prevent rotation ofthe shaft portion in the deployment direction until intentional stepsare taken to disengage the rotational control mechanism, such as toprevent premature deployment of the stent (e.g., when the deliverycatheter is not yet at the target area).

In further embodiments, the handle assembly can include one or morepoints of entry for contrast fluid. For example, as shown in FIG. 7, thedistal coupler 242 can be coupled to contrast tubing 244 to facilitateinjection of contrast fluid through the delivery catheter to the stentregion. The injected contrast fluid aids in imaging the target areasurrounding the stent for purposes of advancing the delivery catheterand positioning and aligning the stent during deployment. The distalcoupler 242 can include fluid-tight seal 246 that prevents contrastfluid and/or recirculating blood from entering the handle assembly. Thefluid-tight seal 246 can include, for example, one or more o-rings. Inother embodiments, the distal coupler 242 can additionally oralternatively include other suitable sealing features. Since in theseembodiments the distal coupler 242 and sealing mechanism 246 may be incontact with recirculating blood, the distal coupler 242 and sealingmechanism 246 can be made of any suitable biocompatible material. Inother examples, other proximal and/or distal couplers in handle assemblycan be coupled to contrast tubing, and/or the handle assembly caninclude other fluid-tight couplers as appropriate. Furthermore, thecouplers for introducing couplers can define a circular, annular spaceor other suitable non-circular shapes.

Selected Embodiments of Methods for Delivering Stent Grafts

In various embodiments, a method for implanting a stent graft at atarget area for treatment of an aneurysm includes: advancing, toward thetarget area, a catheter comprising a tubular enclosure covering thestent graft; positioning the stent graft proximate to the target area;deploying the stent graft; allowing the stent graft to anchor in or atthe target area; and withdrawing the catheter from the target area.Deploying the stent graft can include effectuating simultaneous,opposing translations of first and second handle components such thatthe first the handle component longitudinally displaces the tubularenclosure in a first direction, and the second handle component axiallycompresses the stent graft in a second direction opposite the firstdirection. The method is described further with reference to particularhandle assemblies shown in FIGS. 16A-18E, but the method is not limitedto use of the handle assemblies described herein. Furthermore, thoughthe method is primarily described in regards to deploying a specificdesign of stent graft, it should be understood that the method cansimilarly be used to deploy other kinds of stent grafts or endografts, abare stent, or any suitable kind of stent.

Various aspects of advancing the catheter, positioning the stent graft,allowing the stent graft to anchor in the target area, and withdrawingthe catheter can be similar to those steps described in U.S. PatentApplication Publication No. 2011/0130824, which is incorporated hereinby reference in its entirety. For example, advancing the catheter caninvolve entry into a blood vessel using a percutaneous technique such asthe well-known Seldinger technique.

With respect to deploying the stent graft, in one embodiment of themethod, a practitioner or device operator can displace the tubularenclosure in a proximal direction to expose only a portion of the stentgraft, constrain a distal endpoint of the stent graft in a radiallycompressed state, and axially compress the stent graft to radiallyexpand only the exposed portion of the stent graft. For example, thedevice operator can initially rotate a shaft portion of handle to movethe outer sheath 724 and expose a portion of the stent graft 710 (e.g.,2-3 inches). A delay system can stall any stent graft compressionresulting from this initial rotation, though in other embodiments someamount of stent graft compression can automatically occur during thisinitial rotation. The top cap 722 can still constrain the distal end ofthe stent graft after this initial handle rotation. Proximal movement ofan axial compression slider, which is coupled to the distal end of thestent graft 710 d by leading collet 728, pulls leading collet 728 anddistal stent graft end 710 d proximally, which axially compresses andradially expands the exposed portion of the stent graft, as shown inFIG. 16A. During this time, the practitioner can view, through imagingmethods and/or use contrast fluids and radiopaque markers, therotational and longitudinal orientation of the exposed stent graft.

If not satisfied with the position and alignment of the stent graft, thedevice operator can radially collapse the stent graft down to an outerprofile small enough for stent graft repositioning. In particular,distal movement of the axial compression slider pushes leading collet728 and distal stent graft end 710 d distally, which tensions andradially collapses the exposed portion of the stent graft to a degreesuitable for repositioning. The repositioning process can repeat untilthe practitioner is satisfied. In some embodiments, the method canadditionally or alternatively include resheathing the exposed stentgraft with the tubular enclosure. For example, the device operator canrotate (backdrive) the shaft portion of the handle in the directionopposite that for actuating deployment, in order to reposition thesheath over the previously exposed portion of the stent graft.

When satisfied with the position and alignment of the stent graft, thedevice operator can release the distal end of the stent graft from itsradially compressed state. For example, the device operator can move atip slider in a distal direction to remove the top cap 722 from thestent graft, thereby releasing the distal end of the stent graft, asshown in FIG. 16B. However, the method can involve other actuationmeans, such as rotating a tip screw, to remove the top cap or otherappropriate enclosure.

Once the distal end of the stent graft is released, the device operatorcan simultaneously further expose the stent graft by displacing thetubular enclosure and axially compress the stent graft by advancing theunexposed proximal end of the stent graft as the tubular enclosure isdisplaced, thereby compensating for stent graft foreshortening. Forexample, shown in FIG. 16B, the device operator can manipulate thehandle to induce opposing translations of first and second handlecomponents, where one handle component longitudinally displaces thetubular enclosure (e.g., outer sheath 224) in a proximal direction whilethe other handle component axially compresses the stent graft with adistally-directed force (advancing a proximal end of the stent graft 710d via trailing collet 226).

With respect to deploying the stent graft, in another embodiment of themethod shown in FIG. 17, in a reverse deployment scenario, the deviceoperator manipulates the handle to induce opposing translations of firstand second handle components, where one handle component longitudinallydisplaces the tubular enclosure (e.g., top cap 824 via tip tube 830) ina distal direction while the other handle component axially compressesthe stent graft 810 with a proximally-directed force (e.g., retracting adistal end of the stent graft 810 d via leading collet 828 and innershaft 832).

FIGS. 18A-18E show an exemplary embodiment of the method usedspecifically to deliver stent graft grafts for treatment of an abdominalaortic aneurysm. In this specific application of the method, the methoddeploys stent grafts with D-shaped cross-sections as described in U.S.Patent Application Publication No. 2011/0130824, where the flat portionsof the D-shaped stent grafts press against each other to form a straightseptum and the curved portions of the D-shaped stent grafts pressagainst the aortic wall to form a seal against the aortic wall. Thefigures show and are described with reference to the delivery deviceembodiment of FIG. 6A, but it should be understood that any suitableembodiments and variations of the device can similarly be used in themethod. Furthermore, FIGS. 18A-18E show and are generally described withrespect to the operations of handle of only one delivery device, whichis typically identical to the delivery device used for deploying thedepicted contralateral stent graft.

In FIG. 18A, stent grafts 910 are positioned superior to the aneurysmand partially unsheathed. The catheters of two instances of the deliverysystem have been advanced toward the target area in an aorta usingvarious techniques, such as over-the-wire (guidewires not shown), with afirst catheter advanced along the left iliac artery, and a secondcatheter advanced along the right iliac artery. The catheters have beenadvanced until the top caps 922 and stent grafts 910 are positionedsuperior to the aneurysm, where radiopaque markers can aid correctplacement of the stent grafts. In one embodiment, the catheters crosspaths within the aneurysm such that the distal end of each catheterapproach and/or touch the side of the aortic wall that is opposite theside of entry. In other words, the crossing of catheters may induce astent graft 910 passing through the aneurysm from the left iliac arteryto appose the right side of the aortic wall, and a stent graft 910entering from the right iliac artery to appose the left side of theaortic wall. On each delivery device, rotation of handle portion 952 ahas caused internal threads of handle portion 952 a to simultaneouslyengage first and second lead screws 960 and 962, resulting in proximaltranslation of first lead screw 960 and distal translation of secondlead screw 962. Proximal movement of first lead screw 960 has causedouter sheath 924 to retract and expose a portion of stent graft 910,though top cap 922 still constrains the distal end of stent graft 910.Meanwhile, in a delay system (not shown) as described above with respectto FIG. 6D, distally-travelling lead screw 962 has not traversed thepredetermined delay distance, such that lead screw 962 does not yetaxially compress the exposed stent graft 910.

In FIG. 18B, the stent grafts 910 are slightly axially compressed suchthat the exposed portions of stent grafts 910 are slightly radiallyexpanded. In particular, on each delivery device, the axial compressionslider (represented by box 980), which is coupled to distal bearingassembly 982 in mechanical communication with the distal end of stentgraft 910, has been pulled proximally to axially compress the exposedportion of stent graft 910. As described above, such axial compressioninduces and/or supplements the radial self-expansion of the stent graft910. Since in each device, tip slider (represented by box 990) iscoupled to axial compression slider 980 by removable slider collar 994,top cap 922 moves in tandem with the distal end of the stent graft 910.Additionally, axial compression slider 980 can optionally be moveddistally to tension and radially collapse the exposed portion of thestent graft 910.

In other words, the longitudinal position of the axial compressionslider 980 corresponds to the degree of radial expansion, so the deviceoperator can move the axial compression slider 980 both proximally anddistally to adjust the radial expansion and radial contraction,respectively, of the stent graft 910. Furthermore, the device operatorcan adjust the longitudinal position of the catheter as a whole bywithdrawing and/or advancing the entire catheter, to adjust thelongitudinal position of the stent grafts 910. Partial radial expansionof the stent grafts, when viewed under fluoroscopy by the deviceoperator, aids optimal rotational and/or longitudinal positioning of thestent grafts 910, both relative to each other and relative to the aorticwall.

In particular, each partially deployed stent graft 910 is longitudinallypositioned such that its graft material is aligned with (just inferiorto) a renal artery in order to maximize overlap between the anchoringbare stent portion of stent graft 910 and healthy aortic neck tissue,without resulting in the graft material blocking blood flow to the renalarteries. Additionally, as shown in FIG. 18C, in instances in which thestent grafts 910 are being deployed in a patient having longitudinallyoffset renal arteries, the stent grafts 910 are optimally positionedwith a corresponding longitudinal offset in order to accommodate theoffset renal arteries without sacrificing coverage nor blocking bloodflow to the renal arteries.

Furthermore, each partially deployed stent graft 910 is rotationallyoriented such that the flat portions of the D-shaped stent grafts 910press against each other to form a straight septum and the curvedportions of the D-shaped stent grafts 910 press against the aortic wallto form a seal against the aortic wall.

In FIG. 18C, the stent grafts are longitudinally and rotationallyoriented in the desired manner, and further proximal retraction of axialcompression slider 980 has induced additional radial expansion of thestent graft 910 to cause stent graft 910 to press against the aorticwall. The two stent grafts 910 in conjunction can be radially expandedto a have a deployment radius sufficiently large to form a complete sealbetween them, as well as with the aorta wall superior to the aneurysm.This seal can be verified or confirmed by introducing contrast fluidthrough the catheter (e.g., through contrast tubing in the handles) andviewing whether the expanded stent grafts 910 prevent contrast flowacross the sealed region. Alternatively, other methods of contrastintroduction can be performed to confirm the seal of stent grafts 910against each other and/or against the vessel wall. As described abovewith respect to FIGS. 6C and 6E, axial compression slider 980 lockslongitudinally in place with notches on the housing, in anticipation offull deployment of the stent grafts.

In FIG. 18D, the distal ends of stent grafts 910 are freed from top cap922 and allowed to self-expand against each other and against the aorticwall. If the stent grafts 910 have barbs or other suitable anchoringmechanisms, the stent grafts have become anchored at their deployedposition. On each delivery device, slider collar 994 has been removed toallow tip slider 990 to move independently of axial compression slider980. The tip slider 990 has been moved distally to cause top cap 922 tomove correspondingly move distally and release the distal end of thestent graft. After the distal end of the stent graft 910 self-expands,slider 990 may couple directly to axial slider 980. At this point duringdeployment, the device operator may choose to inject contrast fluidthrough one or both catheters, with contrast couplers described above,in order to verify quality of the seal formed between the stent graftsand with the aortic wall.

Following verification of position and seal, resumed rotation of thehandle portion in each delivery device again effectuates the opposinglongitudinal translations of the first and second lead screws 960 and962. In particular, after the second lead screw 962 traverses thepredetermined delay distance, the first lead screw 960 continues toproximally retract outer sheath 924 and the second lead screw 962distally advances the proximal end of stent graft 910.

In FIG. 18E, the catheters have been withdrawn from the stent grafts 910following full deployment of the stent grafts. The two simultaneousactions of the lead screws 960 and 962 during deployment havecompensated for the displacement effects of stent graft foreshorteningthat would otherwise occur, thereby ensuring that the distal ends ofstent grafts 910 maintain their respective positions during deployment.The stent grafts of FIG. 18E are shown with inferior ends terminatingwithin the aneurysm. However, in other embodiments, each stent graft canextend into and anchor with a respective iliac artery. For example, theinferior graft end of the stent grafts 910 can terminate in the commoniliac arteries immediately superior to the internal iliac arteries so asnot to block blood flow to the internal iliac arteries. However, thestent grafts 910 can be positioned in any suitable manner.

FIGS. 19A-19C show another exemplary embodiment of the method, extendingthat described with respect to 18A-18E. This specific application of themethod deploys iliac stent grafts 1010, each of which couples to andextends a respective stent graft 910 deployed as described above. Thefigures show and are described with reference to the delivery deviceembodiment of FIG. 12A, but it should be understood that any suitableembodiments and variations of the device can similarly be used in themethod. Furthermore, FIGS. 19A-19C depict the operations of handle ofonly one delivery device, which is typically identical to the deliverydevice used for deploying the depicted contralateral stent graft.

In FIG. 19A, stent grafts 1010 are partially deployed adjacent topreviously deployed stent grafts 910. The catheter of each deliverydevice was advanced over guidewires toward the aneurysm and into thelumen of a corresponding stent graft 910. The proximal graft end of eachstent graft 1010 was optimally aligned to be immediately superior to theinternal iliac arteries, so as not to block the internal iliac arteries.However, the stent grafts 1010 can be positioned in any suitable manner.On each delivery device, rotation of handle portion 1052 a relative tohandle portion 1052 b has caused internal threads of handle portion 1052a to simultaneously engage first and second lead screws 1060 and 1062,resulting in distal translation of first lead screw 1060 and proximaltranslation of second lead screw 1062. Distal movement of first leadscrew 1060, which is in mechanical communication through tip tube 1030to top cap 1024, has caused top cap 1024 to advance distally and exposea portion of stent graft 1010. The stent graft exposure began at theproximal end of the stent graft, which radially expanded off of dockingtip 1026. Through a delay system (not shown) as described above withrespect to FIG. 12C, proximally-travelling lead screw 1062 travels apredetermined delay distance before it becomes in mechanicalcommunication with the distal end of stent graft 1010 through innershaft 1032. Once the lead screw 1062 has traversed the predetermineddelay distance, its proximal translation axially compresses the stentgraft 1010 by proximally retracting the distal end of the stent graft1010.

In FIG. 19B, the top caps 1024, and/or associated outer sheath ifpresent, have advanced distally enough to release the distal ends of thestent grafts 1010, thereby freeing the distal end of the stent graft1010. The superior ends of stent grafts 1010 are expanded within in theinferior ends of stent grafts 910, such as to extend the lumens of stentgrafts 910 at a joining within the aneurysm. In other embodiments, thestent grafts 1010 can couple to the stent grafts 910 in any suitablelocation. At this point of deployment, the device operator may choose toinject contrast fluid through one or both catheters, using contrastcouplers as described above, in order to verify quality of seal formedbetween stent grafts 910 and 1010, and/or with the iliac arterial wall.

In FIG. 19C, the catheters have been withdrawn from the stent grafts1010 following full deployment of the stent grafts. The two simultaneousactions of the lead screws 1060 and 1062 during deployment ofcompensated for the displacement effects of stent graft foreshorteningthat would otherwise occur, thereby ensuring that the proximal ends ofstent grafts 910 maintain their respective positions during deployment.

The handle assemblies and stent delivery methods shown and describedherein offer several advantages over previous devices and stent deliverymethods. For example, the handle assemblies provide for straightforwarddelivery of a stent graft to an artery while maintaining initial stentgraft marker positions relative to a destination arterial wall.Embodiments employing opposing screws provide a user with the ability todeliver a stent graft at a high force with relatively little mechanicaleffort. This allows a user to exercise improved control over thedelivery process, such as by enabling the user to control the outerdiameter and/or length of the deployed stent. Further, the mechanismsdisclosed herein provide effective push/pull motion while minimizing thenumber of parts, assembly time, and cost. The push/pull components moveat relative rates according to the predetermined payout ratio (which, inthe lead screw embodiment described above, is dependent on thedifference in pitch between the lead screws), and determine the rate ofstent deployment and degree of stent radial expansion. Such control overthe rate of stent deployment and degree of stent radial expansion canallow the handle assemblies to maintain a low profile and minimize theoverall bulk of the delivery device.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. Certain aspects of the new technology described in thecontext of particular embodiments may be combined or eliminated in otherembodiments. Additionally, while advantages associated with certainembodiments of the new technology have been described in the context ofthose embodiments, other embodiments may also exhibit such advantages,and not all embodiments need necessarily exhibit such advantages to fallwithin the scope of the technology. Accordingly, the disclosure andassociated technology can encompass other embodiments not expresslyshown or described herein.

I/We claim:
 1. A method for implanting a stent at a target area in avessel for treatment of an aneurysm, the method comprising: advancing,toward the target area, a catheter comprising a tubular enclosurecovering the stent; positioning the stent proximate to the target area;deploying the stent, wherein deploying the stent comprises— exposingonly a portion of the stent, radially expanding the exposed portion ofthe stent, and completely exposing the stent after radially expandingthe partially exposed stent; allowing the stent to anchor at the targetarea; and withdrawing the catheter from the target area, whereindeploying the stent comprises effectuating simultaneous, opposingtranslations of first and second handle components such that the firsthandle component longitudinally displaces the tubular enclosure in afirst direction, and the second handle component axially compresses thestent in a second direction opposite the first direction.
 2. The methodof claim 1 wherein radially expanding the exposed portion of the stentcomprises: constraining one end portion of the stent in a radiallycompressed state; and moving the constrained end portion of the stentindependently of and relative to a second end portion of the stent in acompression direction, thereby radially expanding the exposed portion ofthe stent.
 3. The method of claim 2 wherein moving the constrained endportion of the stent comprises pulling a constrained distal end portionof the stent in a proximal direction.
 4. The method of claim 1, furthercomprising forming a substantially fluid-tight seal against a wall ofthe vessel with the radially expanded, exposed portion of the stent. 5.The method of claim 4, further comprising introducing contrast fluidthrough the catheter to verify the seal.
 6. The method of claim 2wherein deploying the stent further comprises releasing the constrainedend portion of the stent to allow the end portion to expand.
 7. Themethod of claim 2 wherein deploying the stent further comprises: movingthe constrained end portion of the stent independently from and relativeto the second end portion of the stent in a direction opposite thecompression direction, thereby radially contracting the exposed portionof the stent; and repositioning the stent relative to the target area.8. The method of claim 7 wherein deploying the stent further comprisesdisplacing the tubular enclosure to enclose the stent beforerepositioning the stent relative to the target area.
 9. The method ofclaim 1 wherein deploying the stent further comprises adjusting at leastone of rotational orientation and axial position of the stent afterradially expanding the exposed portion of the stent.
 10. The method ofclaim 1 wherein deploying the stent further comprises deploying a distalend of the stent before a proximal end of the stent.
 11. The method ofclaim 10 wherein deploying the stent further comprises: longitudinallydisplacing the tubular enclosure in a proximal direction to expose thestent; and axially compressing the stent with a distally-directed force.12. A method for implanting a stent at a target area for treatment of ananeurysm, the method comprising: advancing, toward the target area, acatheter comprising a tubular enclosure covering the stent; positioningthe stent proximate to the target area; deploying the stent byeffectuating simultaneous, opposing translations of first and secondhandle components, wherein the first handle component longitudinallydisplaces the tubular enclosure in a first direction, and wherein, afterthe second handle component has been displaced by a predetermined delaydistance, the second handle component axially compresses the stent in asecond direction opposite the first direction; allowing the stent toanchor at the target area; and withdrawing the catheter from the targetarea.
 13. The method of claim 12 wherein deploying the stent comprisesdeploying a proximal end of the stent before a distal end of the stent.14. The method of claim 12 wherein deploying the stent comprisessimultaneously longitudinally displacing the tubular enclosure in adistal direction to expose the stent and axially compressing the stentwith a proximally-directed force.
 15. The method of claim 12, furthercomprising forming a substantially fluid-tight seal against a wall ofthe vessel with the deployed stent, and introducing contrast fluidthrough the catheter to verify the seal.